Industrial pneumonoconioses, with special reference to dust-phthisis

PUBLIC

299, MILROY INDUSTRIAL

LECTURES

(I915).

PNEUMONOCONIOSES,

WITH

SPECIAL REFERENCE TO DUST-PHTHISIS, BY EDGAR L. COLLIS 3/I.B. ( O x o n . ) , H . M . M e d i c a l I n s p e c t o r of F a c t o r i e s .

Co,#imted from page 263, August "Public Health." BRONCII ITIS.

PrevaIe~tce.--The study of the prevalence of this disease in occupations, as indicated b y mortality statistics, presents certain difficulties, because the disease is most prevalent in the general population at the later ageperiods of life, from 55 years of age and onwards. At these ages, when the days of strenuous physical exertion are past, the occupation followed during the working period of life is less accurately filled in on certificates of death and on census returns, which are the basis of the Registrar-General's figures; while, when the records of Friendly Societies are under consideration, the tendency, owing to bad trade or other reasons, for members, as they advance in years, and can no longer be readmitted, to surrender their membership, causes m a n y deaths from this disease occurring late in life to escape the records. T h e prevalence of a disease in a n y given group of mortality statistics is best indicated by the annual death-rate at various ageperiods per i,ooo living; but, unfortunately, such figures are not always available, and even after great trouble the authorities at Somerset [ l o u s e are unable to deal in this way with some of the most interesting occupational groups. Valuable information, though confessedly incomplete, can, however, be obtained b y examining the causes of death of a sufficient number of persons whose exact occupation is known, without considering the n u m b e r a m o n g whom these deaths o c c u r r e d . If such deaths be classified according to ageperiod, the percentage of all deaths due to a n y special disease at each age-period can be stated. Table 3 contains death-rates from bronchitis at certain age-periods for certain groups for which both the mortality per I,OOO living, and the percentage of all deaths are known; and it shows that when the death-rate per I,OOO living exceeds the standard, the percentage of all deaths as a rule also exceeds the standard. Reversing the process, I think the deduction fair that when the percentage mortality is, at any rate markedly, say 2o per NOTt'2.--'~'he Fro;~tisplece referred to on p 258 faces this h~atalmmR.

HEALTH.

SEeTE,~BeR,

cent., in excess of the standard, the mortality per J,ooo living, could it be obtained, would also be found to be in excess. If, for example, the percentage of deaths at various ageperiods due to bronchitis a m o n g masons who worked on sandstone is taken and compared with that for Lancashire coal-miners, a similarity is present which suggests that the mortality per I,ooo living, could it be obtail~ed for sandstone masons, would, like the mortality per I,ooo for Lancashire coal-miners, be found to be in excess (see fig. 2). Should f o r a n y reason tim mortality from all causes, except the one under considerauon, be abnormally !ow, this method gives an exaggerated idea of the probable mortality-rate per I,ooo living, but it still indicates the relative prevalence of a n y one cause of death. This method is thus far defective, but I desire to dwell on its value, because, from the records of trade societies, and from searches t h r o u g h local registers carried out over a series of years to obtain a reasonable number of deaths, information as to causes of death a m o n g individuals whose exact occupation is known, can frequently be obtained, and can be examined by this method, even when no estimate of any value can be made of the size of the population among whom these deaths occurred. T h e investigation I made (77 d) into the mortality of members of the Operative Stonemasons' Society of E n g l a n d and Wale.4, and of the. United Operative Masons' Association of Scotland, is an instance of the value of ,.his method. Hoffman has called (54) this sta,qstical method " the proportionate m o r t a l i t y , " and he has laid stress upon its value " p a r ticularly in relation to the broad questions involved in tim modern problems of industrial h y g i e n e , " because " i t emphasises the true incidence of preventable causes of death by divisional periods of life . . . . G r a n t i n g tl!e limitations of this method, it remam~ fdr practical purposes, and particularly with regard to the needs of industrial hygiene, the most useful one available." T h e figures of Table 3 indicate that while workers in the open air do not suffer in excess from bronchitis, operatives in certain dusty industries do so suffer, and that this excess occurs sometimes in association with excessive mortality from phthisis, e.g., tin-miners and grinders of metals, and sometimes in association with excessive mortality from pneumonia, e.g., Lancashire coal-miners and dressers of iron castings, but that it is seldom

structure~

ii.

,

i

.~

OCCUPATIONAL HISTORY :-Irenstone Miner (England)~ then G o l d m i n e r (Transvaal), then Ironstohe Miner (E~ngland), then Obldminer (Transvaal) for 5 years, then Ins*~ranee Agent (England) for eight years previous to de'ath. Cause of Death : - - ' P u l m o n a r y (Fubercfflosis. (I) (II) (III) (YV) (V)

Thickened

:

VERTICAL SECTION from Lung of Man who worked at IRONSTONE-MiNING in England and (}OLD-MINING in the Transvaal. Natm'al Size and Natural Colour.

1915.

Fig. 20

PUBLIC

Mortality

2. 25

,~,Rs

I

3 5

o~

45

I

HEALTH.

fi'om

293

Bronchitis

L,~

55

I

65

80

I

25

/

25

J LancashiPs Coal MineP

J f f

20

J

."

J

/°

|5

Pevoentage of All D e a t h s

/

f / /. /

I0

j / / "......~ .o+'*

s

s~

....

~

/

/

.,,"

J

20

•" ° S a n d s t o n e •" " Mason

,."

-""

15

°°"

.'" ,, •"" /

_,-------'~

Occupied and RetiPed Males

,10

,

/

5

0

0

35

35

30

/

/

/ LancashiPe Coal MineP

30

/ 25

Death Rate PeP 1 , 0 0 0 Living

/

2,~

/ //

/ 20

/

/ 15

/ f

/--

i0

20

/

YE.Rs

35

oF

45

L,FE

55

15

/'

"

~

..- f// /

25

2O

/

65

/O(;;cupie.d arid Retined Male~

i0

80

Males

f

Mason

tCut,~,s

Limestone

S=ndsto°o

0"30

35

do.

Slate

do,

Metal & Quartz

75 54

do.

Calcium Carbonate

--

.

[

]

I

.

.

63 291

--

56

1910--1912

.

52

.

0.10 0"44

Sand, C l a y , EmePyf 1 8 9 3 - 1 9 1 2 Metal, Charcoal Metal ~ Quaptz 1 9 0 8 - 1 9 1 2 Metal= Bone,emery do. Linenretc,

0.00

{0.00

278 66

do. do.

.

.

1"29 0"86

1"00

0"~-0 0'00

126

0"46

0"07

Quartz

10

1"0 0"0

7"44 34"961

0"3

0"0

1"o81 2"52 14-981

8"15 2 4 0 6 ~

1"8

1"1

.

.

.

.

--

.

.

.

.

-

.

.

.

-

--

5 " 5 8 : 1 4 " 8 4 27"62 3"57113"00 3 2 ' 4 5 [

0"01

0.0

0"0;

0"0

?

?

0"0

0"0 0"0

2"87, 7"21 2-~'07 i ~0"0

1"52 ' 4"22 t 7 " 9 7

0 " 2 9 1"68 I 6"16 23"29

377

0"09

,0"0~S 0"07

I

1"32

0"46 1"94

0"20

18.821

3"9.__434"62

0"14 I 0 ' 4 7 I 3"06

1"0

1"6

0"0

0'0

0"0

0"6

003 0'18 0 1 6 0 9 6 3-59 10-~31 0.6

0"05

0"16

0'07

3"04 11"57

9"17

8'43

1"18l 3"88 15"22

0"75

1"64

0"95

3"62 14"07

0"32 I 0.9913"65L 1 - ~

0"21

0'23

do. do*

Sawdust

388 704

do. do.

Wool d~bPls C o t t o n debris

0.00

0'05

0.01

0"22

1'06

0"20 l 0"36

0"07

0"22

0"06 0 " 1 7 0 . 4 2

0"05

0.11

0'06

0.03

0"06

0"03

0"08

1'2

0.0

1"7

0'0

1"7 '

2"9

1"6

0.0

1'9 3"3

0"0

1"7

i'2

34

1"2

2"6

1"2

1"7

11

1"6

1"0

0"7

0"7

0"7

1"5

1"8

2'1

4"9

3'8

2"2

4"0

8"6 3"2

5"7

4"8

2"9

,7

4'4

5'1

2"3

2"8

2"2

3"1

1'9

2'6

1"6

1"3

2"5

7"2

10"5

.3"5

7"3

5"3

8"1

10"3

17"2 9"3

8"9

7"2

8"0

53

84

1 ;'1

8"3

3"8

3"4

5"3

5"9

5"2

2"4

2"4

5"7

13"0

9'I

10"7

13"2

23"2

12"1

14"1

15"0

15"7

26"0

5"9

12"6

9'0

excess

~ Calculated f0om data given in Annual Report on the Health of S h e ~ e l d for 1913, pp. xiii-xiv

.k

"~ Calculated from da~a courteously supplied by General Register Oi~ce.

NOTe.--AII figz

•Someexcess ~

In exoess

Low

Noemal

"In exoess

In E x c e s s

Low

Low

LoW

Low

No#,mal

Low

Low

Standard

Excess

I . Excess

In E x c e s s

Low

Low

Norm=l

Low

I~ Excess

In E x c e s s slight e x c e s s In JExcess Low

in Excess Some excess

In E x c e s s

Nominal

~,l,.t . . . . . .

Normal

Low

Low

Low

Low

In Excess

In

Low

Low

Low

StandaP¢l

PNEUMONIA

PREVALENCE OF

5"5

23:5

In E x c e s s

In E x c e s s

~s of the standard for Occupied and Retired Males are underlined,.

No

Excess

Low

11"2 notexoessive n o t excess[¥e

13"1 ~20"0

12'9 16"6

,15'4

23"5 23"6

25"2 20"5 18"9 20"6

1 3 " ( 17'1

11'7

13"1

~!131

10'91 15"4

17'5 ; 25"6

2 0 " 5 22"8

12'6

9"7

10"7

10"4" 13"6

9"8

6"0

5"3

10"2

"~ CaScu'lated from Supplement to Sixty-Fifth Annual Report o[ Registrar-General for Births, Deaths and Marriages in England and Wales, Part II., 1908. Wyman & Sons. (Cd. 2619.)

~ L Slate Qu~.Priel, W o r k e r

, 1 G r i n d e r o f Metals

,}

!

Cston:o.:27

~ s h e ~ e t d ~ Grinders

Dressers o f I r o n Castings

296 172

do.

dO.

Coal~ Shale eto,

436

Clay

do.

170

Coal, Sttsla etc.

0"05

0'00

255

do. do.

Coal only

Mainly Cecil

,Metal; Quar tz,Bonet emePy etc. P o t t e r E a r t h e n w a r e ate. M a n u f a c t u r e Clay and Flint ~ . Tin M i n e r Quartz

S a w y e r ~ Wood T u r n e r Cooper eto. C u t l e r Scissors M~.ker

Cotton Manufacture

Wool Worsted M a n u f a c t u r e

B r i c k Plain Tile T e r r a C o t t a M a k e r

~Lancashi~e

t h ~ South Wales

J N o t t i n g h a m & Derbyshire

0"07 0'05

697 1,182

0.00

0"00

0.00

0"03

do.

do.

I n d o o r led ustPial do.

TeLiloe

Shoemekee

292

do.

O u t d o o r IndustPlal

Shipbuilding

1,509

40,223

71

do.

1900--1902

TOTAL . . . . . NUMBER OF i PER 1.000 LIKING AT AOE PERIOD PERCENTAGEOFALL DEATHS AT AD£ PERIOD PREVALENCE DEATHS OF FROM 5 5 ADd BRONCHITIS 2 0 2535~ 45-- ~55OVER 2 0 - 2 5 SS4 5 - a S - 65AND'oPEl PHTHISIS

do.

Countpy Air

DUST

PERIOD UNDER RENEW

Seaside A i r

Agricultural Districts

TO

EXPOSURE

Death.Rates from Bronchitis for Certain Classes of Males distributed in Age-Periods.

Eisherm~,n

Coal ~Mi. . . . I M . . . . .

/

CLASS

end Retired

Agriculturist

~-Occupted

Table 3 .

I

60 to 61

4 8 to 4 9

61 to 6 2

5 6 to 57

59 to 6 0

49

49

52 54 t o 55

6 0 to 61 5 6 to 57

55 to 56

61 to 62

58 to 59

4 7 to 4 8

4 7 to 4 8

54 to 5 5

54

6 2 to 6 3

61 to 62

5 8 to 59

59

over 67

57 to 58

I

MEDLAR ACE AT DEATfl FROM ALL CAUSE3

:4~

L~

Pigmented Nodule.

Same Field seen by polarised light.

FIG. 3 . - - C O A L

MINER'S

LUNG.

(North Staffordshire). The presence of dust other than coal is indicated by the polarisation of light.

(a) Free Carbon particles in air vesicles with several phagocytic cells taking up the particles into their cytoplasm.

(b) Carbon particles in the lymphatic spaces of air cells and perivascular channels

(c) Fibrous and pigmented nodule.

(d) Pigment associated fibrous change.

FIG. 3 . - - P L A T E

I.

with

general

(e) Pigment in the lymphatics of the deeper layer of the pleura.

(/)

(g] General deposition of pigment in a bronchial gland.

Small lymph gland containing pigment.

(h) Pigmented and fibrous hyperplasia of bronchial gland,

(i) Mesenteric gland with comparatively little pigment.

FIG 3 . - P L A T E

II.

(For this Series (~t) ¢o (i) I am indebted to Dr. F. Shufflebotham

1915.

PUBLIC H E A L T H .

found associated, at the same age-period, with excessive mortality from both phthisis and pneumonia. To establish a relation between dust inhalation and the prevalence of respiratory diseases among coal-miners, some reference to the nature of the dust to which these men are exposed is necessary. My predecessor in this lectureship, Dr. Shufltebotham, remarked (55) that "fibroid lung is rare amongst coal-miners, and anthracosis does not seem to entail disablement," but he pointed out, just as Dr. Trotter had previously done (87) , that coal-miners are exposed not merely to coal dust, but also to dust of the strata in which the coal is found; and Oliver has suggested (94 a) that " when a coal-miner's ltmg shows pronounced fibrosis, it is generally an indication that the individual has worked in a coal seam which contained a quantity of stone; it is the stone dust in the coal, not 1he coalitself, which . . . is the cause of the fibros i s " (see fig. 3). Probably the prevalence of respiratory diseases among miners depends on the amount and the character of the stone dust present. The influence of coal-dust itself which has been carefully investigated (88) in America by Dr. W a i n w r i g h t and Dr. Nichols is remarkable. These workers, having first ascertained that statistical data from every available source agreed in establishing that coal-miners are singularly free from phthisis, exposed guinea-pigs for about two months to the inhalation of coal-dust, and then in~ected a culture of tubercle bacilli into them. Such anthracosed animals developed " extensive tuberculosis of the abdominal viscera and of the glands r o u n d the tracheal injection, but ttre lungs were free," while control animals developed "extensive tuberculosis of the lungs and abdominal viscera." Such facts are evidence that coal-dust in some way protects against phthisis. Coal dust then is not itijurio.us,, bdt, hecahse it can be easily distinguished, it is .useful to demonstrate the path by which dust enterg and travels through the lungs. First it reaches the~alv:edii, w h e r e it is taken up by phagocytes (see fig. 3a); these carbon pigmented .phagocytes pass through the walls of the air vesicles into the lymph channels and deposit their pigment in the perivascular spaces (see fig. 3b). Should the lymph chapnels in any place be blocked by fibrous tissue, the pigment collects there, whether the blocking be localised (see fig. 3c), or diffuse (see fig. 3d). It is found particularly beneath the pleura (see fig. 3el; and also

"295

in the puhnonary glands (see fig. 3f), and in the bronchial glands (see fig. 3g), where also it accumulates where there is fibrous tissue (see fig. 3h). In other lymphoid tissue, however, for example, file mesenteric glands (see fig. 3i), comparatively .small deposits are to found. Broadly speaking, in Durham and Northumberland coal lies in nearly horizontal seams, and is got with a minimum disturbance of other rock; while in Lancashire the coal seams, though resembling those of Durham and Northumberland in thickness, lie at a steep inclination and much intervening rock has to be " ripped." The Nottingham and Derbyshire coalfield in this respect resembles the Durham and Northumberland field, and the mortality from respiratory diseases, bronchitis and pneumonia, among the miners on t h e two fields is low. Exposure to dust arising from intervening rock in.the Monmouth and South Wales coalfield resembles that of the Lancashire field, and the mortality from bronchitis and pneumonia among the miners on these two fields is high. At the outset then the form of respiratory disease which follows upon dust inhalation is found to vary with the ldnd of dust inhaled; and bronchitis, which occurs in excess when ever there is exposure to injurious dust, appears to be par excellence the chief of the pneumonoconioses. The imporlance of bron.. chitis as an indication of the injurious properties of a given dust has been somewhat overlooked for two reasons (i) the excessive mortality from phthisis experienced in some dusty industries has overshadowed it, and (if) bronchitis is a complaint which advances slowly, and, though causing incapacity, does not cause much mortality during tile worldng period of life. P r o b a b l y when invalidity statistics of occupat;ion become available, this disease will 'sta~{d out clearly as the chief cause of inValidity i~* dusty occupationS. Causation.~-The curves, Shown in :fig. 2, which represent the mortality from bronchitis /~CvarioffS age-periods am~ong those exposed to dust inhalation, are similar (only at a higher' level) to that f o r the general population, suggesting that the disease in the dust groups is due to the same influences, only in intensified form, as produce the disease in the general population. This method of obtaining a clue to the causation, in any given group, of a disease which also occurs in the general community appears to have been first used by Givre (a7b), though the abscissa of

296

PUBLIC H E A L T H .

his curves were calendar years a n d n o t ageperiods. The value of this method will be more apparent when dust-phthisis is under consideration. The causation of bronchitis in general, leaving on one side the influence of microbic invasion, may be summed up as any stimulation of the bronchial mucosa which determines such an inflammatory hyper~cmia of the walls of the air passages that an execs• sive exudation of mucus results. Dust suspended in inspired air falls on the walls of the bronchi and bronchioles; and, to be re~ moved, must be entangled in mucus and swept back by ciliary action until it can be expelled by coughing. To effect this purpose the secretion of mucus and the ciliary action increase with the amount of dust inhaled. Increase this process beyond physioJogical elasticity and there occur degeneration and destruction of the ciliated mucosa, and, synchronous|y, a mechanical ballooning of the alveoli, emphysema, which is produced by frequent coughing to remove the unusual amount of mucus secreted. Other influences besides dust may over-stimulate the bronchial mucosa, but the important part dust plays is shown by comparing the incidence of the disease among fishermen and agriculturists with that among classes who live in atmospheres more laden with dust. While the influence of dust in general in the causation of bronchitis may be accepted, certain dusts do not appear to exert such an influence. T h u s coat-dust, unmixed with other material, e.g., Durham and Northumberland miners, is not associated with bronchitis. And, although mortality statistics are not available, careful investigations made in France (56 ) into the manufacture of plasterof-Paris, and by Arlidge (4oc), whose observations a m o n g alabaster workers I can personally confirm, suggest that calcium sulphate belo.ngs to this class. Investigations as to the effect of limestone on masons made by Barwise (57) in Derbyshire, by Howard in the Isle of Portland, and myself (58 ) among masons .. in m a n y districts, indicate that limestone dust has no marked effect in causing bronchitis, and recent mortality figures stated in Table 3 justify this conclusion. Pure clay, as contrasted with highly siliceous fireclays, seems also to have no effect. Inquiry into the manufacture of cement (59), and mortality figures for cement workers, which only show 23 deaths from bronchitis out of a total of 293

SEPTF,MBER,

---i.e., 7.8 per cent. as compared with 8.4 per cent. for Occupied and Retired Males--necessitates the addition of cement to the list, notwithstanding the amount of dust generated (60) in its manufacture and its hygroscopic nature. Nor is there any evidence that dusts of animal origin, such as bone, leather and horn, when unmixed with other things, conduce to bronchitis. On the other hand, the data of Table 3 show that exposure to the inhalation of certain dusts is associated with a high mortality from bronchitis; the mortality among masons who dress sandstone places sandstone dust in this list; the mortality of Lancashire coal-miners condemns dust of the strata between the coal seams; the mortality among potters must be ascribed to flint dust; that of tin-miners to quartz d u s t ; a n d that of cotton operatives and wood workers to dust arising from the materials they manipulate. To this list may be added from clinical evidence dusts of flax (38d), jute (6z), hemp (z4), slag-wool (59a), glass and emery (53). These dusts differ widely in origin and in chemical composition, but possess the following common properties : (i) such brittleness as leads them to break into fine dust; (ii) insolubility in the normal secretions of the air passages; and (iii) nonplastic (i.e., probably non-colloidal) structure.

Clinical Symptoms.--Bronchitis induced by dust is essentially a chronic disease. Cough, and free expectoration of sputum coloured with the dust inhaled, are the primary symptoms which are directly referred by the worker to his occupation. If the period of exposure has not been unduly prolonged, absence from occupation is followed by cessation of the symtoms which, however, return when work is resumed. Dr. E. S. Reynolds, with his knowledge of the industrial conditions of Manchester, has described (93) at this stagic the existence of a fine tribe bronchitis dspecially prevalent a m o n g those exposed {o emery dust; a condition which he considers is, in adults, seldom seen apart from exposure to dust. After more prolonged exposure the bronchitic condition becomes so established that only slight improvement follows upon rest; and, sooner or later, the symptoms usually associated with chronic bronchitis appear, shortness of breath and other signs of cardiac distress. These are, however, well-known, and need not be restated here.

FIG. 4. S K I A G R A M (taken by Dr. Gouldesbrough) of an apparently healthy man after 14 years' exposure to fine emery dust in the manufacture of emery paper.

F I G 5. S K I A G R A M (taken by Dr. Gouldesbrough) of an apparently healthy man after 27 years exposure to fine glass dust in the manufacture of glass paper. 2v~OTE.--Skia, grams of workers exposed for shorter periods to these dusts showed similar but less marked shadows.

PUBLIC H E A L T H .

1915.

Differential D i a g n o s i s . - - W h a t has been said of clinical symptoms shows that the diagnosis of pure dust-bronchitis cannot be safely made from the study of an individual case, but only from previous knowledge of the exposure of the individual to dust, and of the known effect this dust has in causing bronchitis. Even then, since bronchitis occurs in the general population, the influence of dust inhalation only raises a question of probability in the causation of each case, a probability which the presence in the sputum of dust known to be associated with excessive bronchitis supports. W h e n present in an indivMual in whom dust inhalation has caused p u l m o n a r y fibrosis, or the barrelshaped chest typical of asthma, the physical signs of these conditions may indicate the connection between dust inhalation and the disease; but when it is present in individuals exposed td such dusts as emery, glass and slag-wool, unless the fine tube bronchitis described b y R e y n o l d s is present, there may be nothing to distinguish the case from any ordinary case of bronchitis. If a group of individuals is under examination, the unusual number and the early age of those affected may suggest the origin of the trouble; and at one factory where exposure to dust of emery and powdered glass was in excess, although no history of any prevalence of phthisis a m o n g the workers could be obtained, and although no definite signs of fibrosis could be detected, I found an unusual number of men, as may be seen by referring to Table 4, in the prime of life suffering from bronchitis, emphysema, and having an average chest expansion below normal. Table 4

EXPOSURE

Nature E'ngllged

TO

EMERY

AND

of WoPk

NumbeP ~-xamihed

in d u s t y P P o c e s s e s

50

r

GLASS

DUST

Number with Chests Showing; S i g n s of D i s e a s e 13 26 Pet" Cent,

Y~Pd LabouP, Enginemen~c,

Exposed to General of t h e F a c t o P y . ~

Dust

25

2

8 Per

Cent.

This dil.alinution in chest expansion whichis characteristic of dust inhalation is also a ch~u'acteristic of chronic brollchitis;"as ,als~a, is the presence of emphysema, although this condition is less .marked when pulnaonary filorosis is piesent. A correct diagnosis, t h o u g h often difficult to arrive at, is of importance in advising tim patim~! as to the future; and some help mhy be obtained from radiography, for evidence does show that the changes induced in tile I~r~inchia! nlucosa m a y be detected as s h a d o w s wl,Ach in size and distribution coincide with

297

the ramifications of the air passages, and differ mar!:edly from the shadows thrown in cases of dust-phthisis. These shadows resemble those seen in cases of marked bronchitis of other causation; and t!my are more marked as the exposure to dt~st has been more prolonged (see figs. 4 and 5).

Patt~ology.---The degeneration of the bron chial mucous membrane, and the condition of emphysema coincide with those described for ordinary bronchitis in every text book, and require no repetition here. After death dust particles will not often be detected; for the disease is of its nature slow, causing prolonged incapacity, and recent exposure to dust inhalation must, therefore, be exceptional. PNEUMONIA. Prevalence.--If, as seems practically certain, dust inhalation is an influence which predisposes the bronchial mucosa to attacks of bron6hitis; and if, as will be discussed later, dust inhalation can also modify the parenchyma of the lungs so that it is peculiarly prone to succumb to tuberculosis, then dust inhalation can hardly be expected to leave unaffected the intermediate zone of tile lungs, the bronehioles and alveoli, the site of a distinct form of p u l m o n a r y disease, pneumonia. Yet dust inhalation as an influence predisposing to pneumonia is not widely recognised --indeed, neither Dr. P. K i d d in his Lumleian lectures (66) nor Sir James Barr in his address on pneumonia (63) allude to such an influence. But there is no a priori reason against it, for pneumonia has certain etiological characteristics in common with Other respiratory diseases; bronchitis is probably due, as a final cause, to microbic invasion of the bronc}dal walls; and phthisis and pneumonia /ire certainly due to microbic invasion of those" parts of tile r e s p i r a t o r y apparatus, which are the sites of these two diseases. A Committee appointed by the Royal ~ollege .of:Pl,.ysicians has_ r~ported (64) that in the spread of phthisis among human beings inhalation of infected dust appears to be the more important means of infection; an opinion strongly supported by the recent work of Chauss6 (IOI); and Dr. R. R. A r m s t r o n g holds (6,5) that " t h e r e seems reason to believe that all forms of pneumonia, not excepting lobar pneumonia, are inhalation infec~ lions." Dr. Kidd, it is true, considers (66a) that pneumonia is primarily a blood infection,

298

PUBLIC H E A L T H .

but while doing so he leans to Calmette's view that tubercle bacilli reach the lungs vigt the blood stream through the intestine ; and so still recognises a common path of infection. Further, an interesting inverse relation exists between phthisis and pneumonia; thus Kidd, during his extensive clinical and post-mortern experience, has observed (66b) that "lobar pneumonia complicating declared and progressive tuberculosis of the lungs is exceedingly rare," and has raised " t h e question whether there is not some opposition between the two diseases." Now, this opposition is suggestive, for it is found in the mortality statistics of dusty industries (see Table 5); and, as will be seen later, pathology suggests, at any rate for those exposed to dust inhalation, a reason for this antagonism. Hence the prevalence of pneumonia among operatives exposed to certain dusts, but who do not suffer from dust-phthisis, and the absence of any prevalence of pneumonia among operatives who do suffer from dust-phthisis, point to dust exerting a definite influence upon the prevalence or non-prevalence of pneumoni a . In mortality statistics lobar pneumonia and broncho-pneumonia are grouped together, and this fact compels a conjoint consideration of these two forms of respiratory disease, although the special investigations, from which evidence as to a causal relationship between p n e u m o n i a and dust inhalation, is drawn, have generally had reference to the occurrence of lobar pneumonia. In late age-periods of life broncho-pneumonia often drops the curtain on cases of chronic bronchitis, and so swells the mortality figure for pneumonia in a group with a high death-rate from bronchitis; and the effect of this statistical method of considering the two diseases together must be kept in mind when mortality rates after the age of 55 years are examined. Various authorities have maintained that a conflection exists between dust inhalation and pneumonia. Merkel held the opinion (4od) that people employed in a dusty atmosphere suffer in a higher proportion from croupous pneumoriia than others, I-Iirt considered (74) this disease is immediately caused by dust, and West states (47 a) that " the victims of dust inhalation . . . are exposed to greater risk than others of acute p n e u m o n i a . " Pneumonia among workers exposed to basic slag dust (pseudo-pneumonie h scories) has been carefully investigated by Monnier (68) and b y Gautret (69). These observers have found

SEPTEMBER,

the pneumobacillus of Friedlander, and the pneumococcus present, either alone or together, in these cases, and also slag dust; and have described the symptoms as similar to, but more severe than those of ordinary pneumonia, and they look upon prognosis as particularly grave. Helm and Agasse-Lafont, when reviewing (4 I) these researches, admit the possibility of traumatic lesions to the respiratory organs, due to the inhalation en masse of caustic dust, lesions which prepare the way for the multiplication of microbes, usual inhabitants of the air passages, with the development of bronchitis and of pneumonia. Aufrecht, of Magdeburg, also states (96) that pneumonia is prevalent among slag workers, affecting in two years 48 per cent. of the men at one works; and he further found that the disease among these men had a case fatality of 3o per cent. In the same connection interest attaches to the inquiry carried out by Ballard for the Local Government Board into Middlesbrough pneumonia; he concluded (7o) that " slag dust, to which the epidemic had been attributed, was not the cause of the pneumonia, but that, when from any cause pneumonia becomes epidemic, persons largely exposed to the inhalation of this dust may and do suffer more than persons not so exposed, and that the disease with them is of high fatality." This question of high case fatality has also been noted when pneumonia occurs among those exposed to other dusts; thus in the case of dressers of iron castings (see Table 5), their trade secretary told me that information of a member suffering from pneumonia is nearly invariably quickly followed by news of his death; while VV~atkins-Pitchford, when referring (44) to cases " s u g g e s t i v e of an acute bronchop n e u m o n i a " among native gold-miners in the Transvaal, says, " i n such cases the patient dies after'a Mlort illness," and haattri2 butes the disease " t o the inhalation of very large quantities of dust over a short i~eriod." On the gold-fields attention has been centred on the study of dust-phthisis, still Purdy, after an investigation in New Zealand and Tasmania, found (7x) a high incidence of pneumonia in the mortality returns of quartzmining districts, and he considers " t h e damage done to the lungs by inhalation of irritating dust makes a suitable soil for the pneumococcus " ; and Summons gives (72 ) the mortality per I,OOO from pneumonia, I9o5-o6 , among Bendigo miners as 2.74, as

Indoor

Tailor

~q

Manufacture

Dressers

etc.

Dressers

Qu~rr`ier

r M~tal

Slate

Lima)stone

-.Sandstone

do.

45

36

do,

Slate

49 67

do. do.

147

Carbonate

1910-1912

8andn C l a y Emer¥~ M etat~CHarcoa

Calcium

Quartz

Metal ~ Quartz Metal, Bone,Emery Linen~etc,

Sand, Clays Emery MetRIF C h a r c o a l

91

19

31

119

do. do.

1908-1912

83

1898-1912

258

do. do.

.Metal~ Q u a r ` t z e B o - e l Emery eto, Clay and Flint Quartz

Sawdust

d~bPIs

599

!do.

Cotton

149 264

do.

353

do. do.

409

do.

Clay

etc.

Coal9 Shale

104

do,

Wool ddb~ls

etc,

Coal

C o a l wS h a l e

Mainly

2~2

do.

617

892

~Z92

0'59

0"52

0"17

0'25

0'41

0"34

0"55

Io~-8~

__

.

0"6g

.

0'22

0'47;0'41

.

0 " 2 0 [1 " 5 6

0'44

0"46 0'6;3

0"28

0"60 0"36

10"54 1"01

0"430'73

0"19

0"15

0"33

0"26

0'350"60

0"11

0 '20 0"24

0"39

2">51'81

I

1'38 2 "10 8'94

2'9713'70

1 "64 1'99

I "36il 6"09

"89 5"13 2"11

1"24

.

.

2'28

2'37

1"00 2"60

1"20 2"10

0"86

6 "92

.

2~92

2'80

3'53

3"80

--

~

3"93

7"00

6"92

5"41

6"21

1"23 2 "2? 4 "72 i 1"8712"21 5"49

1"08 2".214"02

1"11

1"02

1"55 2"821~'13

1 " 0 0 1"9,_313"74 6 ' 0 S

0"72[0'89

0'48!1

0"78[ 1 '4912 "07 3"76

0"70 i 1 '64

1"16

1"06 0"73

]1 " 1 6 2 " 7 7

2"65:4"35

45-- 55-

0"5510"81

1'17

358'4

6 "2

12'8

6"2

6"3

9"0

1 5 "0 12 '0

4'4

8 "7

4 "3

9'0

31"4

0"0

6 '7

8 "6 1 3 ' 2

~ 9" 5

33"3 27"7 10"0

8'3 3 '2 "938'8

1 "4

7"4

11"1 1 5 " 4

9"5

7 '1

7"7j

23"3i18

12'5

112"5

- 5 "7

7 ' 4 11 "8 5 "0 20"2

11'2

7"9

9"9

S '1

8 "2

9"6

4"7

8'7

9"7

45-

11"2

23"1

8"5

7 '8

7 '4

5"0

28"2

5"8

7"3

8 "1

9"9

10"4

9 "3

9 "6

1 7 "2 1 6 " 2

1 0 " 4 11 "8 1 0 " 8

4"510"5

14"81

12'0

7'1

7"5

6 '5

13"2

8"6

1 0 "S

10'8

35-

12"__6113"51"~'1

5"1

11 '1 1 6 " 7

8"6

5 "O

3 '1 ! S "4

6 "3 B 5 "2

6 "4

10"7

1"8

5 "1

8"7

25--

4 "8

5 '1

s'8

4 '1

3 '3

3 "5

3 "5

4 '1

2"0

3"5;:

4"1

3'2

16"9

7"5

5:7

8"2

6°0

14'5

3"g

S" 0

5"9

Jf Calculated fror~ data courteously supplied by General Register Office.

~ Calculated from data given in Annual Report on the Health of Sheffield for 1913, pp

....

Low

Low

Low

Low

LOw

E~cess

Excess

Normal

in

In

LOW

Low

Low

PHTHISIS

PREVALENCE OF

In Excess

In E x c e s s

In Excess

Low

~n E x c e s s

In E x c e s s

]n E x c e s s

3'1

N O T E , --AIl figures in excess of the standard for Occupied and Reth'ed Males are underlincd.

(Cd. 2619.)

In Excess

4 "4 S o m e e x c e s s .... late in life

2 "8 n o t e x c e s s i v e

4'0

G "9

3'9

5 "4

2 "5

5"2

5 "1

Normal

4 "6 slightexces~8'11 4 "5

8"5

5 ' 4 t 3 "7

9 "5

1 2 '1

9'4

6"7

6'0

E "1

5 "6

9"6

G'O

G '4

7"5

55-

~SAND OVER

PERCENTAGEOFALL DEATHS AT AGE PERIOD

~S AHO OVER 2 0 -

PER 1,000 LIVING AT AGE PERIOD

")iCeCalculated from Supp]ement to Sixty-Fifth Annual Report of Rcgistrar.Gencral for" Blrths, Deaths and Marriages in England and Wales, ;Part II., 1908. XVyman & Sons.

Worker

ere,

M~nufactune

and Glazers

L~ut'e's

Sheffie|d/Grinders

of Iron Castings

Earthenware

Potter

Miner

Sciesoes Maker

-Cutle~

Coop6r

M;~slufactupe

Cotta~Makep

W~Jes

Derbyshire...

Sawye~ & Wood Turrler

Cotton

&

& South

Tile Terra

Wool Worsted

Plain

]Stone Getter` Dresser | Mason

/

-!

f

Monmouth

~Lancashi~e

Brick

~Tln

"

~ /ivliCnOeapIs< N o t t i n g h a m

~-Durham ~ NoPthumbePla~td

do.

Industrial do,

do.

57

do.

614

• 1027

34

FROM PNEUMONIA 2 0 -

TOTAL NUMBER OF DEATHS

do.

1900-1902

REVIEW

PERIOD UNDER

do,

Industrial

Coal only

Outdoor

ShoemRker

Air

S e a s i d e Air,

Country

Shipbuilding

Fisherman

Districts

EXPOSURE TO DUST

Death-Rates fi'om Pneumonia for Certain Classes of Males distributed in Age-Periods.

kales

AgPicul~u~,al

~tnd R e t i r e d

Agriculturist

f --Occupied

CLASS

Table 5 .

54 5(; to 57 ~light excess

53 49 In Excess

Low

In "Excess

51 to 52

4 2 tO 4 3

62 -to53

53 In E x c e s s Low

5 7 tO 5 8 In E x c e s s

45 47

48 to 49 48 to 49 In E x c e s s In ExceSS

In EXCESS

51 to 52 |n Excess

In Excess

53to

In Excess

54

45 to 49 Norms|

44 to 45" In E x c e s s Normal

4 3 1:o 4 4

EXCESS l a t e in life

49

51

52 Normal

Low some excess l a t e tn l i f e

4 5 t o 4"/ Normal

59 to 60

80 to 51

MEDIAN AGE A T DEATH FROM PNEUMONIA

Low

Low

PREVALENCE OF BRONCHITIS

L~

800

PUBLIC

compared with 1.2~ for adult males in Victoria, i9o3-o5; but, as neither observer states the age-distribution of the pneumonia cases, the usual contradistinction between the incidence of pneumonia and phthisis when due to dust, though it may be surmised, cannot be definitely asserted. This contradistinction, however, according to Bremridge's observations quoted (9") by Oliver, exists on the I(olar gold-field in India, where " miners' phthisis is remarkable rather for its absence than its presence," but " a large proportion of the miners die from p n e u m o n i a , " induced, however, it is thought by other causes than dust inhalation. Similarly, Dr. Haldane informs me, miners' phthisis is l~.ot known in the gold-mining district of Cripple Creek, Colorado, where, though dust is freely generated by rock-drills, the workings are not in

Table 6.

action of dust his lungs quickly develop the same condition as was seen in these animals, and therefore he is very liable to attacks of the organism of acute p n e u m o n i a . " In later years fibrosis, which, as will be shown later, is inimical to the occurrence of pneumonia, developed, and synchronously phthisis increased and pneumonia diminished. The figures of Table 6 show well the effect of initial exposure to quartz dust, and the altered mortality which follows prolonged exposure. Another industry in which dust in generated, and in which pneumonia has been stated to be unusually prevalent, is the slate trade; in this industry, according to evidence referring to Merionethshire slate quarries given (76) by Dr. Evans and by Dr. Richard Jones in 1895 , and reiterated (77) by the iatter in 1912, pneumonia is unusually prevalent

DEATHS FROM PNEUMONIA GOLD MINERS IN WESTERN

C a u s e ot' D e a t h

AND PHTHISIS AUSTRALIA,

Pneumonia

Phthisis

1900--04

1905

A g e - Pe Piod

45

AND

OgER

49

78

Percentage of All Deeth~ fl,,om All Causes 1 "59

1"00

49

23

Percentage of All Deaths from All Causes

45

AND OYER

3B

44

1 "16

I "00

57

48

11 "9

7"S

2"1S

-- 09

9"3

Number,

quartz, but in a hard, siliceous rock. On other American gold-fields, where the gold is in quartz, miners' phthisis appears to exist. Pneumonia at Cripple Creek, though no information is to hand as to its prevalence, is recognised to be very fatal, but this is ascribed to the elevation of the district---io,ooo feet above sea-level. In the gold-mining industry, however, the best evidence of the occurrence of pneumonia comes from Western Australia (73), where Dr. Cumpston, the Royal Con> missioner., of Igio , reports that about 19oo " many men took on machine work for the first time (witil excessive exposure to dust), and therefore the death-rate from pneumonia was h i g h " ; after finding that experimental exposure of a,_~i:.-nals to massive inhalation of dust produced a pneumonic condition of the lungs, Dr. Cumpston concluded " that when a young man first becomes exposed to the

1 5 TO 4 4

13 "2

Proportion

Propol, tlon

AMONG

Age-Period 1 5 TO 4 4

Number

SEPT~I~I>mZ,

HEA LTH.

1'00

1 "19

1 '00

among rockmen, miners, and tabourers who work underground in the slate quarries, while phthisis is not in excess. In France fibrosis of the lungs, attributed by Dr. Sejournet to dust inhalation, has been described (97) among slate workers at F u n l a y ; but phthisis does not seem to
P U B L 1 C H E A L TH.

1915.

an outbreak of p n e u m o n i a , and that he is a c c u s t o m e d on the occurrence of such a storm to set aside beds in the hospital for the reception of the inevitable crop of cases. T h e most interesting statistics, however, are those from the coal trade, which have already been referred to when bronchitis was u n d e r discussion. In certain districts, viz., the coaltields of D u r l i a m and N o r t h u m b e r l a n d , and of D e r b y s h i r e and N o t t i n g h a m s h i r e , the death-rate from p n e u m o n i a is u n u s u a l l y low, while in other districts, viz., the coal-fields of Lancashire, and of M o n m o u t h s h i r e and S o u t h W a l e s , it is u n u s u a l l y high. U n f o r t u n a t e l y for the present purpose, coal-miners are exposed to dust of coal as well as that of interv e n i n g strata; a n d since the low death-rates from phthisis experienced b y coal-miners in e v e r y c o u n t r y (88) compel us to admit that coal-dust has a definite i n h i b i t o r y effect upon the prevalence of phthisis, the presence of the usual inverse relation between the prevalence of phthisis and of p n e u m o n i a loses its significance. Interest, however, attaches to the pneumonia death-rate, the p r o p o r t i o n a t e mortality for which a m o n g L a n c a s h i r e miners is h i g h for e v e r y age-period, an evil distinction o n l y shared in T a b l e 5 b y dressers of ironcastings, a m o n g w h o m also the phthisis mortality, t h o u g h not so low as a m o n g the miners, is not h i g h . T h e dust of dressing shops is of interest in that it contains a high proportion, 79 per cent., of free silica, and yet exposure to it has not been f o u n d (as will be shown in the next lecture to be usual when free silica is present) to be associated with a h i g h phthisis mortality, t h o u g h it is with a h i g h mortality from bronchitis a n d p n e u m o n i a . Another dust c o n t a i n i n g free silica, which does not seem to predispose to t~hthisis, is that of clay mixed with quartzite, used in the m a n u f a c t u r e of. ce/;tain re{ractory bricks ; but such evidence as can be o b t a i n e d suggests that e x p o s u r e to this dr, st is associated with a high mortality from. b r o n c h i t i s a n d - p n e u m o n i a . Simi!ar4y dust of Attoft's shale, which is known to contain over 3o per c e l t . of free silica, does not >ceils_

it.> ~..~~,t_ii~os~. r .~

~z). p i l t h i . b l b , , ~ . , ~ ....

~o; . . . . . .~.t-~'" .

301

action of silica in p r e d i s p o s i n g to phthisis, while leaving in relief its power of predisp o s i n g to p n e u m o n i a and bronchitis, especially as the p o i n t .is undecided w h e t h e r the same sequence of evefits f o l l o w s tile inhalation of s i m i l a r . d u s t in certain b r a n c h e s of the p o t t e r y i n d u s t r y . I may, however, s a y that certain investigations, now b e i n g carried on b y Dr. I t . C. Ross, suggest that this action of clay ill m o d i f y i n g the influence of silica dust, which a p p e a r s to be similar to that exerted b y coal, depends on the presence of certain o r g a n i c constituents in these materials. C o n c l u s i o n . - - P n e u m o n i a appears to be predisposed to b y the inhalation of those dusts which are associated with an u n d u e prevalence Of b r o n c h i t i s ; some of these dusts are associated with an excessive m o r t a l i t y from phthisis, a n d some are not. A n d when tile phthisis m o r t a l i t y is not in excess, the pneumonia m o r t a l i t y is in excess t h r o u g h o u t occupational life; but when the phthisis m o r t a l i t y is in excess, this excess occurs at those later age-periods which represent p r o l o n g e d exposure, while the excessive m o r t a l i t y from p n e u m o n i a occurs at those earlier age-periods which represent initial exposure. C a u s a t i o n . - - T h e i n f l a m m a t o r y processes in the lungs which constitute an attack of p n e u :monia are caused b y the multiplication of m i c r o - o r g a n i s m s in the p u l m o n a r y alveoli and b r o n c h i o l e s ; a n d the p n e u m o c o c c u s of F r a e n kel is the chief t h o u g h not the o n l y microo r g a n i s m which can initiate such inflammation. T h i s p n e u m o c o c c u s is a normal inhabitant of the u p p e r air passages, a n d a n y influence which interferes with the vitality of the lower air passages m a y be expected to increase the p r o b a b i l i t y of microbic invasion, whether that influence be alcohol i m p a i r i n g ciliary aeti6n (4ia), or cold, or traumatism, either acute (Jue to local injury, or chronic, due to dust inhalation. As in the case of bronchitis, the curve rep'~es¢.nting the. mortSlity °from p n e u m o n i a at various age-periods a m o n g th()se exposed t,', ,dust inhalation sufficienllv re~;embloq, *b,o~l~*!~ all_ a h i s g i m t

lexcl.

~.hag I t ) r t i n : g c ) ) ( * t a i

l.)i~,I:~.-

tion to the occurrence of other respirator}, discase.~ ia i~ot kl~ox~n. T" ,L~.e t.lttC~F'l dHst5 al-12

tion to sugges2 that (he iniquencu \vhi
,~O

-,i~i!:ll

ltt.f

.~illt 11~_lf

a~aoc~atcd

\xitlt

t 1tat.t.

[ t I t2'~

t:la)

in

t'()!t!g!i)l

\ttl-v!!ta

t r('~"

~; I) (';.1

))~im::~

~.tt~ ~ l n ( ) l l a l i t x \\at\

it

I('I)I~ ",~'ilt~

:t, [~

1!1

,i

t,, 1!!~' I ~iJEl~'Ia~t. ",\1~i¢ !~ ~l~ !('tliitl:~

q

I)F-,.>I)~)!'I!<)V~>,.

lq the present atatc of our knto~\iedge speculation ~s ,u,c ~t,~ to why, as tile facts seem to indicate, the presence of clay modifies the

l>~)])iit.ti,,!a ('ieases

i.,:., JL I:~ ali ~llliu(';l((~

i}1¢2 i i ; l } ) ] i i J v

(see fig'. 6).

[o

pl]l!tll't]()¢ i)t,citl

x~],i,t,

~,-

!:l\:t",i,,l~

PUBLIC

302

HEALTH,

SEPTEMBER,

FIG.6 20

c/,....

25

35

45

t

vE"ns °rur~

55

65

t /N "O~-PEnIoDS t

J

.. ,°

Dressers

''.

,0

Mineps

................

0

--

Oo©upled and Retinal Males ..... England and Wales 19OO-O2

• ,%

."

*°

.

5

°

.*

-o

Peroentsge o f .'' All D e a t h s ." at certain Age- P e r i o d s

0

Coal

=

.,°

• "

5

5

of Iron Castings

Lancashire •

8

""

0

"• "° J

,5

5

,____.._..~

I(

"-~--~-,_

.......

E)

...

5

U

7

j"

6

Death Rate Per 1 ,OOO Living at cePtain Age- PePiods

/ / /

5

///

4

f

tJ

~

"

,/

J

J

J

// 3

/ / j"

J

s

J

2'

i I

J

tt

J

f

0!

J

I

OI 20

2

I

Z

il

1

--I25

i

I I

I

35 rEans or ur~ 45

/M

AOt-Pfn/ODS

55

I I 65

i

10

8O

PUBLIC HE.dL TH.

1915.

W h e t h e r we agree with K i d d (66a) that p n e u m o n i a arises p r i m a r i l y as a blood infection, or with A r m s t r o n g (65) that all forms of p n e u m o n i a are inhalation infections, the conclusion still holds good that some pred o m i n a t i n g influence is at work which produces in an e x a g g e r a t e d f o r m the same statistical type of m o r t a l i t y a m o n g those exposed to the inhalation of certain dusts. T h e p r e v a l e n c e of p n e u m o n i a in certain d u s t y occupations, already alluded to, suggests that inhalation of dust of the following materials predisposes to the disease, viz., hasic slag, some forms of slate, the strata in which coal is found, silica when mixed with clay, cotton, w o o d ; but that the disease is not f o u n d in excess a m o n g those exposed to the inhalation of dusts c o m p o s e d of pure coal, clay, or of those dusts associated at certain age-periods with excessive phthisis mo.rtality; that is to say, p n e u m o n i a is p r o b a b l y above the a v e r a g e a m o n g all persons exposed to dusts which cause bronchitis with the exception of persons exposed to dusts which also cause phthisis, and even a m o n g these persons it is above the a v e r a g e d u r i n g the earlier years of exposure. T h i s latter fact p r o b a b l y indicates that the pathological changes, to be discussed later, which pave the way for t u b e r c u l a r infection, are inimical to p n e t n n o n i c infection; and in the fact that those c h a n g e s involve to a large extent the obliteration of the alveolar spaces and bronchioles, the areas specially concerned in pneumococcal inflammation, m a y lie the cause for the inverse relation noted between the prevalence of p n e u m o n i a and phthisis in d u s t y industries. Moreover, the occurrence of a high death-rate from p n e u m o n i a at early age-periods in such occupations as the m a n u facture of pottery, tin-mining, and dressing sandstone, in which phthisis is prevalent in later- age-periods, suggests that, if' such obliteration of the special p n e u m o n i c areas did not o c c u r , the p n e u m o n i a death-rate woujd continu'e excessive "througl~ol~t, qK~q. P n e u m o n i a , [" .... v . . . .". . P . . . . tO b v ;'~'~

J

303

c h y m a of the lungs, rather than the lining epithelium, finds in tibrosed tissue with its impaired vitality suitable m e d i u m for g r o w t h . T h u s is provided, some explanation of tile diverse m o r t a l i t y ra'tes from r e s p i r a t o r y diseases experienced in dusty industries, all dusts which are insoluble in the fluids f o u n d in the lungs, and which are of sufficiently smali size to be inhaled, impair the functional activity of the respiratory r~ucosa, and are influences predisposing" to b r o n c h i t i s and p n e u m o n i a , while of these dusts those, which b y their presence in the p a r e n c h y m a of the lungs, determine fibrous formation with obliteration of the seat of election of pneumonic activity, cease after a time to predispose to p n e u m o n i a , but continue to predispose to bronchitis, a n d at the same time introduce a new factor b y p r e p a r i n g the way for tubercular infection. Before a c c e p t i n g a p u r e l y mechanical ex.planation of the occurrence of p n e u m o n i a in d u s t y industries, the possibility that other properties of dust or other adverse influences are necessary to reinforce the effect p r o d u c e d b y the presence of inert particles of dust must be considered. Briault exposed (78) guineaopigs, some to silica dust, some to nitrous fumes, some to silica dust and nitrous fumes, but only with the c o m b i n e d exposure obtained m a r k e d s y m p t o m s of acute p u l m o n a r y inflammation. Similarly Prof. Beattie tells me that in his extensive experiments (77 a) on animals with m a n y kinds of inert dust, t h o u g h he obtained m a r k e d congestion of the vessels of the alveolar walls and some exudation, he did not p r o d u c e definite p n e u m o n i a which could be attributed to dust inhalation. In basic slag dust G a u t r e t considers (69) the lime and p h o s p h o r i c acid present m a y reinforce the mechanical action of the dust particles; in other dusts, e.g., that of iron dvesse
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PUBLIC H E A L T H.

infection cannot be thrown back, e.g., massive dust inhalation, and, according to Cesa Bianchi (4za), indulgence in alcohol, or (iii) chronic interference with the activity of the p u h n o n a r y epithelium, for instance by dust, so reinforced by other adverse influences, e.g., illness, over-fatigue, nitrous fumes, that a normal a m o u n t of infection cannot be resisted; and these determining influences may act with varied power and in a n y combination.

Cli,l~ical [email protected] acute nature of this disease prevents those affected from continuing at work ; for this reason I have not been able to study the disease at first hand. Others, however, have noted, particularly Ballard, Monnier, and Gautret, in their respective investigations into basic slag pneumonia, that the incidence of the disease is not so n mch increased as is the case fatality; and, as already mentioned, a high case fatality prevails among dressers of iron castings. Gautret says that in cases of basic slag pneumonia the symptoms are more profound, accompanied at times by severe or even fatal h~emoptysis, the affected area is more diffuse and more often bilateral than in ordinary cases; and that convalescence is slow and accompanied with mucopurulent sputum suggestive of phthisis, but that tubercle bacilli are not found, while final recovery negatives this suggestion. Cases of pneumonia, however, in the origin of which dust has ptayed no part may exhibit such characteristics; and apart frorn this increased caseseverity I have been unable to find any definite indication that pneumonia as it occurs a m o n g those exposed to dust differs clinically in any way from p n e u m o n i a in general, nor indeed, if the causative influence suggested above is accepted, is such difference to be anticipated. Differential Diaguosis.--Just as in the case of bronchitis, the connection between the disease and dust inhalation must depend upon an intimate knowledge of the occupation followed, of the exposure to dust, and of the inortality~ prevalent in that occupation. A correct diagnosis is of importance because, with the known tendency to a fatal termination, every case from its onset, hOwever apparently slight, must be considered serious and treated accordingly. Detection in the sputum of particles of dust known to be associated with pneumonia may assist in diagnosing the occupational origin of the attack.

~EV't'~v~3~.,

Pathology.-Theoretically excessive exposure t o dust might be expected by mass influence to be followed by excessive secretion from and proliferation of the alveolar cells, thus causing an acute form of broncho-pneumonia ; and such cases have been described (44) by ~,Vatkins-Pitchford in which " t h e lungs are found post-mortem, to be deeply congested, oedematous, and finely mottled with islands of p i g m e n t a t i o n , but exhibit none other of the characteristic appearances of fibrosis," and he ascribes these cases to the inhalation of very large quantities of dust over a short period. Such cases, however, are rare. P r o b a b l y when exposure has been prolonged signs of chronic bronchitis will always be found associated with those of pneumonia, but, except in so far as dust particles may be detected in the tissues after death, as, for instance, in W a t k i n s - P i t c h f o r d cases, in which " m i c r o s c o p i c examination with polarised light shows the connective tissue to be laden with siliceous particles and the alveoli to be distended with serous exudate and catarrhal cells," and in those of Gautret in which basic slag dust was found, no pathological condition has been described which differentiates pneumonia as it occurs in dusty industries from pneumonia as it occurs in the general population. (To be continued.) LIST

OF

REFERENCES.

1. Second Report o] the Royal Commission mt Metalli]erous Mines and Quarries, ~9~4, pp. 133-15E. Wyman & Sons, Ltd. (Cd. 7476.) ia. Ibld. p. 141. lb. /hid. p. x44. 2. ChemicaI Pathology, 2907, p. 392. H. G. Wells. W. B. Saunders & Co., Philadelphia. 3. Prepared from Supplement to Sixty [i#h At~mtal Report o] the Registrar-Genera! oaf Births, l)eMhs, and Mt~r*iages in Engtnmt nnd Wales, part ii., ~9o8 Wyman & Sons, Ltd. (Cd. 2619,) 3a. The Soot]all oJ Londolz. 'rh~ Lancet, 6th Jan., ~9~2. 4. Coal Smoke Abatement in England. Dr. Louis Ascher. Journal of I#,oyaI Sanitary Institute, Vo!. xxviii., 19o8, p. 89, 5. Antiquity o] Man. Sit" Charles I,yelh 6. Origin o] the Aryans, p. 18i. Dr. Isaac Taylor. 7. The Date o] Grime's Graves and Cissbz~ry Fl'ilzt Mines. Reginald Smith. Soclety of Adt~quarle.% 9tb May, 1912. 8. Minutes o] Evidence. Royal Commission on MetaZli]erous M;~les and Quarries, Vol. ii., 19~4, appendix J., p. 2 6 2 . Wyman & Sons, Ltd. (Cd. 7477-) 9. Annales D'Hygibne FubIique. T. Sixi~me, p. xo. Benoiston de Chateauneuf. i83L Paris. Io. (gzr'ores complbtes d'Hippocrate avec le tbxte Gr~c en regard; par E. Littrd, Vol. 5, I846, P- J67. J . B . Bailli~ere, Paris~ H. A Treatise o] the Diseases o.[ Tradesmen, writlen iu Latin by Bern. RalnazMni, Pro]essor of I'l',yslck at Padua, and now done in EItglish by Dr. James, 17o5, p. 14. London. ~2. Ibid. p. i63. a3. lbld. p. 3o. • ~4. Ibld. p. i75. I5. Ibid. pp. 17o-i71. I6. Call Pllnii Secuudi, Historice, IValurMis, lib. vii., see. i. x7. Ibid. llb. xxxiii., see. xl. I8. De Re Metallica, Georgii AjIricolce , 1557. Froben Basil. 19. Bericht yon Bergwercken, durch G. E. Lohneiss, folio, 16qo~ p. 56. Stockholm und ttamburg. 20. The Sta[Jordshlre Potler, by Harold Owen, I9o~, p. a76, Gra~.t Richards. Zl. Trans. Medic. Chirurg. Soc. Edinburgh, Vol. i., p. 373, 1824. Alison. 22. My Schools aim Schoolmasters, Hugh Miller, ~869. Twelfth Edition. William P. Nimmo, Edinburgh.

191,5. 23.

PUBLIC HEALTH.

The Effects o] Arts, Trades and Pro]esslons, C. T u r n e r T h a c k r a h , ~832, Second Edition, p. 99. Baines & Newsom, Leeds. Ibld. p. 9o. Ibid. p. 55Ibid. pp. 85-86. Ibld. p. 89. Ibid. p. 95. La Tuberculose chez les ouvriers en sole. Th~se, D r . P i e r r e Giw'e, ~889. Lyon. ,7 a. Ibld. pp, ~4i-2. -'27b. Ibld. pp. 92-3 . 29. The Vital Statistic.* o] Sheffield, G. C a l v e r t Holland, ~843, p. ~93. Robert T y a s . London. 3 o. |bid. p. :96 and p. 2as. 3 ~. Report o] the Commissioners appoiuted to inquire into the conditions o/ MMes in Great Britain 1864, apper~dix B., pp. 347-43 ~ Eyre & Spottiswoode. 32. IbM. p. 333. On Stone-Masons" Phthisis, G. L. G u l l a n d , M.D., M a r c h , ~9o9 E d i n b u r g h Medical J o u r u a h 34. Report on the Ilealth o] Cornish Miners, ~9o4, p. ~ . Eyre & Spottlswo~de. (Cd. 209L ) 3.Is. Ihid. p, I8. 34 h. Ibid. p. 2o. 34 c. Ihid. p. 24. 34 d. Ibld. p. ~9. 33, Archly. j , r pathos. Analom. und I'hysioL und ]ur ken. Medic. yon Pircho~v, bd. xxxix., p, 44 ~ 36. O n lere.ch il[iilslone-mahers" Phthisis. Medico C h l r u r g i c a l Review, VM. 25, ~86o, pp. 2~4-224, T . B. Peacock. And Trans. Pathol. Sac. London, Vol. xii., ~86o, T . B. Peacock, and Ibld.. Vol. xvli., x866. 37. Papers *elating to the sanitary state el the people el England, General B o a r d of I ] e a l t h , 1858 , p. ~32. Eyre & Spottiswoode. 37 a. I131(I. p. 63. 38. Third Report o] the Medical O~'cer o] the Privy Council, 1860, Appendix VI. 38a. Ibid. p. 133. 38b. l h l d . p. 142. 38c. Ibld. pp. x74- 5. 38d. Ibld. pp. ~5~-2. 38e. Ibid. p. ~ 9 . 39. Fourth Report oJ the Medical Officer oJ the Privy Council, ~86~, Appendix IV. E y r e & Spottiswoode. 39 a. Ibid. p. 14539 b. Ibld. p. t77. 39 c. Ihld. p. ~59. 39 d. Ibld. 1/. ~62. 39 e. lbld. p. I66. 4° Diseases o] Occupation, J. T . Arlldge, ~89a, p. 245. P e r c i v a l & Co. 4oa. Ibid. p. ~-97. 4oh. Ibld. p. 3~3 . 4oc. Ibld. pp; ~98-9 . 4od. Ibid. p. 252. 41. Efjet des poussi~3res industrielles dans la production des affections broncho-pulmouaires, f l e i m et Agasse-LMont. Trans. XVlIth I n t e r n a l . C o n g r . of Medic v x9~3. see. xviii., pt. it. 4~a, Ibid. Discussion, p. 23. 42. Presse 3fdd. ~st Sept., 19o6 , Calmette. 43. Lead Poisoni, g and Lead Absorption, l , e g g e and Goadby, i 9 t 2 , p. ~oe. E d w a r d Arnold. 44- The Iudustriat Diseases o/ Sonth A#i~a, ~,Vatldns-Pitchford, ~9~4 T h e Med. Jourll. of South Africa. 45. Floating Matler of lhe Air, John T y n d a l l , 188t, pp. 26- 7. I,ongroans, G r e e n & Co. 45a. Ibid., p. '37. 46. The Ash oJ Silicotic Lungs, John McCrzie, ~9x3. T h e South African I n s t i t u t e for Medical Research. H o r t o r & Co., Johannesburg. 47. Diseases el the Organs el Respiration, S. West, Vol. i., x9o2. Griffin & Co., Ltd. 47 a. Ibid. p. ~96. 48.~ Report el Royal Commissioner o~ hnl,lonary diseases amongst Miners, ~9xo, ]Perth, W e s t e r n . A u s t r a l i a . 48a. lbld. p. 68. 49- Miners" Phth, is s at Bendigo, W. S u m m o n s , x9o7 . Stillwell & Cb[, Melbourne. 49 a. Ibld. p. 38. 49 b. I b i d . . p . 35. 5o. Flax Mills and Linen Faclories, E. H. Osborn, x894 , pp. ~g-zL ( C . - - 7~87.) E y r % & Spottiswoode. 51. Jl[r. A. G. Finlaison's Repc:rt-on A')ck~ess a~ut Mo1"Fality~ F r e n Z y Sdcieties' Return~ ~853 , p. xxi. ! 52. Sichness and Mortality Experience o] the [.O.F. Manchester Unity durMg tbe Five Years, ~8e)3-~897, 19o3, p. 66. Manchester. 53. Amlual Report of the ,ChieJ Insbector o] Factories .[or too& pp. zo3-5. W y m a n & Sons, L t d . ( C d . 4664 .) 54. Industrial Accldents and Trade Diseases (n the United States, F. L. H o f l m a n . T r a n s a c t i o n s of the [qfteenth I n t e r n a t i o n a l Congress on H v g l e n e and D e m o g r a p h y , VM. I., P a r t it., pp. 764-769. I913 , ~Va~-hington. 55. The H~gienlc Aspect oJ the Coal-mlnin~ Industry, Milroy I.eet m e s 1914, F. Shufllebotham, lecture iii'. 56. Mon3graphie hygidnique de la jahrication d~ pldtre en France. H 6 b e r t , Maute, and H e l m , I 9 ~ - D u r u y et Cir., P a r i s 57. Report on the Prevalence oJ Phthisis among Quarry Workers and jlliners, S. B a r w i s e , i9x 3. D e r b y County. 58, Royal Commission on MetalliJerous Mines and Ouarries. M i n u t e s o1 Evidence, Vol. iii., Appendix P., i9~ 4. W w n a n & Sons, L t d . (Cd. 7478.) 23a. 2425. 26. 28. 27.

305

Annual Report el the Chic] Inspector o] Factories Jar /9z, ", pp. 203-5 . W y m a n & Sons, Ltd, ICd. 6239.) 59 a, Ibid. pp. 23o-1. 60. ]ahresberichte der Gewerbe-Aussichtsbeamten und Bergbehorden lur des Jahr. z g H , pp. 384-419 . Berlln. 6i. On tt, e Mortality el Flax Workers, C, D. P u r d a h , 1873. 62. Jute, H . J. W i l s o n , D a n g e r o u s T r a d e s , edited by T . Oliver, i9oa , p. 66o. John M u r r a y . 63. An Address on Pneumonia, Sir James Bar~. B r i t i s h Medical Jmwnal, Jan. Ioth, ~914 . 64. Report to the Royal College oJ Physician,s on the InJectivity el Pulmonary Tuberculo.~is. British Medical J o u r n a l , April t l t ~ : ~9~4. 65. The Experimental Productlou o[ Pneum,llia, R. B. Armstrou~l. S u p p l e m e n t to B r i t i s h Medical journal~ July i g t h , i 9 1 4 . 66. The Lumleian Lectures, Dr. P. b:idd, L a n c e t , Voh i., 1912. 66a. ibid, p. i59o. 66b. Ibld. p. 1668. 68. Les Pneumonies d stories, Monnier. Gaz. Med. de Nantes, Nov. I2th, 1898. 69. Les Pneumonies a scories, G a u t r e t . Tb.6se de Pacts, 1899. 7 o. Final Report of Departmental Com,!liter ~ Cerlaiu Miscellaneons Dmlgerous Trades. p. i3, 1899. F.yre c- Spottiswoode, (C,950%) 7 I, The Cause, Effect, Incidence and Prevention o] Pueumonoconios;s of Quartz Miners, J. S. Purdy. The Practitioner, February, lqt2 72. Mblers" Phthisis at Bendigo, W Summons, i9o 7. StillweII & C o , Melbourne. 73- Report o] the Rayed Commissio~er on Pulmonary Diseases amo~qst Miners, p. 69, 19io. P e r l h , W e s t e r n Aust}atia. 74. Die Ntaubinhalalions-Kral~kheile~l, I)r. L u d w i g H i r t . Die Kranl,:i~elten der A r b e i t e r , E r s t e r T h e i l . Breslau, 1871. . 75. Diseases oI the Lungs. Powell and [Iartley, Fourth Edition, i 9 t i , H . K. I.ewls, London. 76. Report o] Departmental Committee upon Merionelhshire Sla!e Mines. 1895. ( C . - - 7692.) Eyre & Spottiswoode. 77. Minutes o] Evidence, Royal Commission on'Metalliferous ,][l'~ws and ()uarri~s, Vol. ill., 1914, p. 113, \\:ynaan & Sons, l.td, !Cd 7478.) 77 a, Ibid. pp. I45-154. 27 b. Ibid. p. x88. 77 c. lbid• p, 236. 77 d. Ibid. pp. 181-i89, and Appendix P. 78. Recherches experimenlales sur :vs comtitions physiologiqnes du travail des ouvriers sableurs, ~91~. lh-iault. Th6se du Paris. 79. Report of Medical O]~icer o/ [Iealth ]or the City oj Aberdeen I9o9, p. io7. 80. Report on the prevalence o] Lung Diseases amol*g the Workers at Grinshill O.arries. J. W h e a t l e y , ~9.~2. S h r e w s b u r y . 8L Report o] a Commission o~ ,Mi~ers' Phthisis and Pulmoltary Tuberculosis in South A#ica. i 9 t 2 , pp. 7-~o. C a p e T o w n . 82. Report o: Medical OffÉcer o] Health el Jaham~esburg. \st J~dv, • 2"912, to 3olh June. xgi 3. Charles Porter, M . I ) . , p. 20. Johamw~,.burg. 83. Transactions o[ the Pathological Soclely o] London, Vol. xx., 869 . 83a. Ibid., Vol. xvl. i865, pp. 59-60. 84. Science ]rein an Easy Chair, a second SelqeS, 1912 , Sir Ray L a n k e s t e r , pp. i9~-2. Adlard & Son, 1.ondou. 8.5. Rabelais. A ue~v lranslatlo~. \V. F. S m i t h . ~893, Vol, h, chap xxix., p. 343. A l e x a n d e r P. W a t t . 86, Die llygiene des Berg'mannes, Halle, 10o3. G o l d m a n . 87, The so-called Anthracosis aild Phlhisis iu Coal-nliners, R. S. Trotter. B r i t i s h Medical Journa!, 23rd May, ~9o3 . 88. The Relation between An.lhracosis and Pulmonary Tuberculosis, by J. M. W a i n w r i g h t and I t . J. Nichols, A m e r i c a n Journal of the Medical Sciences, ~9o8, Voh cxxx., pp. 4o3-414 . 89. Miners' Phthisis. Sir T . Oliver, British Medical J o u r n a l , '~21h Sept., ~9o3 . 9 o. Weavers" Cough, A n n u a l Report of the Chief Inspector of Factories for ~9~3, p. ~5o. W y m a n & Sons, l a d . (Cd. 749L) 9 L Diseases oJ the Lungs ]ram Mechanical £'anses, G. Calvert [I,Aland, i843 , ,p~ 23. John Churchill, 1,andes. 9~a. Ibid. plh". 36-7 . 9~b. Ibid. p. 60. 9~. Disease'd "of O&upation, Sh- "r. Oliver, p. 2"9.t. ~9o7. M e l h . , m & Co. 93. Report oJ Departmental Committee on (ompensation jgr l n l , s trial Diseases', ~]:iin~les o] Evide ce, pp. i972~o2' 19o7. (('d. 3~96 ) W y m a n & Sons, L t d . ~4. Pneumonoconiosis, Sit-. T . OHver. Sy.;tem of Medicine, AI!batt ~,[i~d RelICs/off, V o k v.¢ i9o9, p. ~469 M a c m i l l a n & "('o., I,td. 9.t a. Ibid. p. 462. 95. Staubinhalation mM Staubmetastase, Juliu,~ Arnohl, ~S,qs. 96. Erkranh*¢ngen des Respirationsapparates, E. Aufr~,cht, N o l h n a ~ . V , SpecieIle Pathologb, unc T h v r a p e, Bd. xlv. 97- La Maladle des A~d,,isiers : la Vchisl,,,~,, l~.,'h~ ~,.,~ i , ~ i , , : Matot-Braine. 9£. Proceedings op h',,y.t S,,,i¢ly .[ Ucdhine, I(l~,'tt. TL, : : q c a ~ [ . a l Section, Voh vi., ~9~4, pp. 93-98. 99. Proceediugs of R,,val 5ocielv o[ Medici.,., P a l h ~ + , / i ~ a l %.cth,~, Vol. vii., p a r t ill., ~gL l, TuborculMd l ' . , u m o u , , c o n h , . i ~ , ~. t; Sherlock, Ioo. The Relation el IndustrlaI aml S , uitarv Conditions to l'aope>icm, Mr. A. D. M a i t l a n d and Miss Rose Squire p. ~o9, and" pp. i25-6 ~909. W y m a n & Sons, L t d . Cd. 465.3.) SOL Annales de l'Institut Pasteur, P a r i s , ~914, xxvlil. ~oz. Staubinhalationskrankheiten der Lunges, p. ~7~, Z e n k e r . Io 3. Deutsch. Archiv. fiir k i l n . Medic. Bd. 2, 1867. Ibid. pp. u 6 - t 7 a 59.